The use of inkjet printing systems in offices and homes has grown dramatically in recent years. The growth can be attributed to drastic reductions in cost of inkjet printers and substantial improvements in print resolution and overall print quality. While the print quality has drastically improved, research and development efforts continue toward improving the permanence of inkjet images because this property still falls short of the permanence produced by other printing and photographic techniques. A continued demand in inkjet printing has resulted in the need to produce images of high quality, high permanence, and high durability, while maintaining a reasonable cost.
In inkjet printing, the inkjet image is formed on a print medium when a precise pattern of dots is ejected from a drop-generating device known as a printhead. The typical inkjet printhead has an array of precisely formed nozzles located on a nozzle plate and attached to an inkjet printhead array. The nozzles are typically 30 to 40 micrometers in diameter. The inkjet printhead array incorporates an array of firing chambers that receive liquid ink, which includes pigment-based inks and/or dye-based inks dissolved or dispersed in a liquid vehicle, through fluid communication with one or more ink reservoirs. Each chamber has a thin-film resistor, known as a firing resistor, located opposite the nozzle so ink can collect between the firing resistor and the nozzle. Upon energizing of a particular firing resistor, a droplet of ink is expelled through the nozzle toward the print medium to produce the image. The printhead is held and protected by an outer packaging referred to as a print cartridge or an inkjet pen.
However, there is still a need for pigment-based ink having stability, low viscosity, and compatibility with multiple solvents and paper types, as well as being able to produce images of high gloss, uniform area fill, and good black/color mixing, while maintaining a reasonable cost.